The majority of the sEMG signal from the pelvic floor musculature is less than 100 hertz (Hz). The instrumentation should have the ability to filter noise interference allowing for a clear signal to be displayed. To detect the majority of the pelvic
musculature signal, the instrumentation should have a wide bandwidth filter of 30 to 500 Hz. As the muscle fatigues, a shift to the lower frequencies (Hz) occurs; therefore, a wide bandwidth allows signal detection of low-amplitude contractions.9 A 60 Hz "notch" filter rejects power-line interference. As all electronic instrumentation has internally generated noise, it is important for the clinician to know the internal noise level in order to distinguish noise from the sEMG signal.
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